BACKGROUND Coronary artery disease (CAD) patients receiving antiplatelet agents occasionally undergo craniotomy. We aimed to clarify clinical outcomes after craniotomy for unruptured intracranial aneurysm (UIA) in patients with CAD. We also aimed to identify the possible predictive factors for morbidity and surgical complications in patients on antiplatelet treatment. METHODS We retrospectively analyzed 401 consecutive patients who had undergone craniotomy for UIA at our institution between January 2006 and December 2016. Forty-three patients (10.7%) received antiplatelet agents during the perioperative period. The underlying reasons for antiplatelet treatment were CAD in 12 patients and other diseases in 31 patients. RESULTS Severe morbidity and intracranial hemorrhage occurred more commonly and symptomatic brain infarction occurred less frequently in patients with CAD compared to patients with other underlying diseases (16.7% versus 3.2%, 16.7% versus 9.7%, and 8.3% versus 16.1%, respectively), though differences between the two groups were not significant. Univariate analysis revealed that a low preoperative baseline platelet count was significantly correlated with the occurrence of intracranial hemorrhage (cutoff value, 16.5×104/µL; odds ratio (OR), 46.67; 95% confidence interval (CI), 3.88-561.95; p=0.0005), and a high baseline platelet count tended to correlate with severe morbidity (cutoff value, 29.8×104/µL; OR, 11.33; 95% CI, 0.88-145.52; p=0.0550). CONCLUSIONS Our results suggest that surgical complications and clinical outcomes after craniotomy may depend on the underlying reason for antiplatelet treatment. Moreover, a preoperative platelet count can be useful in predicting the occurrence of intracranial hemorrhage and severe morbidity after craniotomy in patients receiving antiplatelet agents.